1. Field of Invention
The present invention relates to the technical field of plant irrigation, particularly relates to an embedded type, inverted-filtering and anti-clogging emitter, and a drip irrigation pipe (tape) having the embedded type, inverted-filtering and anti-clogging emitter.
2. Description of Related Arts
Drip irrigation is an irrigation method directly conveying water and nutrient required for the growth of crops to the soil around crop roots uniformly and accurately in a smaller flow, by taking water with certain pressure pass through a piping system and an emitter(s) mounted on a last level of pipe (capillary). Drip irrigation avoids damaging soil structure, makes water, manure, air, heat keep in good condition that is suitable for the growth of crops, has little evaporation loss of water, avoids the appearance of surface runoff, barely has deep leakage, and has became one of the most water saving irrigation technologies so far.
Drip irrigation may be divided into surface drip irrigation and subsurface drip irrigation modes. For the surface drip irrigation, capillary is arranged above the ground; for the subsurface drip irrigation, both capillary and emitter (water dripper) are buried underground. Compared to the surface drip irrigation, subsurface drip irrigation has effects of better water saving, soil saving and environment conservation, and increasing yields as well.
Emitter is a core component of a drip irrigation system, and its role is to take water spread around under the emitter in a manner of unsaturated flow in soil as water drops or seeps in a constant low flow through the emitter, by using the energy dissipation and pressure reduction of the tiny flow channel of the emitter. In order to make drip irrigation system truly achieve the desired objectives, the emitter shall meet the following requirements: (1) it is small, uniform and stable in discharging flow, and is little in sensitivity to water pressure change; (2) it has good anti-clogging performance; (3) it has a simple structure, is convenient to manufacture, lay and install.
At present, there are three kinds of commonly used emitters (water dripper) of drip irrigation systems, which are mono-wing labyrinth type, embedded type, and pressure compensated type. Therein, for the mono-wing labyrinth type, a side or a middle part of the pipe is overall hot pressed once to form various shapes of flow channels while manufacturing thin walled pipe. For the embedded type, the previously manufactured emitter is embedded in the capillary during the manufacturing process of the capillary. For the pressure compensated type, the shapes of the elastomer component or flow channel are changed in virtue of water flow pressure, so that the area of the section over the water surface changes, thereby causing the outflow of the water dripper small and stable. At present, all the above several emitters (water dripper) adopt the method that directly arranges tiny flow channels with turbulent state for the emitters to achieve in energy dissipation and pressure reduction. It not only requires for high accuracy of flow channel manufacture, by a slight deviation of which, a great effect on the outflow capacity of the emitter may be caused, but also usually configures a flow channel section of 0.3˜1.0 millimeter, to cause the large flow cross-section generate larger pressure loss and smaller flow rate at the position of water dripper, whereas such configuration with single and tiny flow channel is apt to cause clogging, and even by increasing investment of filtration and other facilities, it is still difficult to be avoided, especially difficult to prevent biological and chemical clogging.
However, if slightly enlarging the cross-section of the flow channel, it would be less prone to controlling flow rate, which not only is waste of water, but also affects the uniformity and effectiveness of irrigation.
When the current commonly used drip irrigation pipes (tapes) are employed for surface drip irrigation, there still exists problems of being prone to clogging, higher requirement in water quality and poor uniformity and the like; moreover, the clogging problem would be even worse as being employed for subsurface drip irrigation. Therefore, it is a key issue to promote further development and application of drip irrigation that how to synchronously solve the flow control of the drip irrigation and the problem of preventing the clogging of the drip irrigation of the drip irrigation system.